Traditional overdenture attachments, "cement-to" abutments and screw retention abutments are useful in implant restorative dentistry. Most free-standing overdenture attachment, "cement-to" abutments and screw retention abutments are designed to screw into an implant fixture. In multi-tooth restorations, a plurality of implant fixtures are used to support a prosthesis that is fabricated using an impression. While such systems have proven advantageous, they have not been widely implemented in part due to problems associated with the nonparallel placement of implant fixtures. If the fixtures are significantly nonparallel, undercuts are present which prevent "draw" of the prosthesis that is to be placed on the attachment/abutments. Also, many attachment systems are designed with the assumption that the attachments will be parallel. Such systems either will not function or function ineffectively otherwise.
There is therefore a need to provide techniques that overcome the problems associated with and/or compensate for nonparallel placement of implant fixtures.